If your old R10 has a working hard drive you can simply pop it into the eBay R10. You'll need to perform a "Clear and Delete Everything" before you can use it to record anything, though.
Lots of additional Tivo upgrade resources in the "Tivo Upgrade Center Forum" at http://www.tivocommunity.com.
Lots of additional Tivo upgrade resources in the "Tivo Upgrade Center Forum" at http://www.tivocommunity.com.